CVE-2021-1647

Microsoft Defender Remote Code Execution

7.8 HIGHActively exploited (CISA KEV)EPSS 39.4%

Published12 Jan 2021
Added to CISA KEV3 Nov 2021
Remediation due17 Nov 2021

Description

Microsoft Defender Remote Code Execution Vulnerability

CVSS 3.1 breakdown

Attack vectorLocal

Attack complexityLow

Privileges requiredLow

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Security Essentialsall versions

Microsoft System Center Endpoint Protection2012

Microsoft Windows Defenderall versions

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

Patch & vendor advisories

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1647PatchVendor Advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1647PatchVendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1647US Government Resource

Frequently asked

Is CVE-2021-1647 being actively exploited?

Yes. CVE-2021-1647 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021.

How severe is CVE-2021-1647?

CVE-2021-1647 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 39.4% probability of exploitation.

Which products are affected by CVE-2021-1647?

Affected products include Microsoft Security Essentials, Microsoft System Center Endpoint Protection, Microsoft Windows Defender.

How do I fix CVE-2021-1647?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-1647 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation works Book a demo

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.